Build tutorial codes together with other samples

These codes should be included into regular builds.

samples/cpp/tutorial_code/features2D/SURF_FlannMatcher.cpp

@@ -83,7 +83,7 @@ int main( int argc, char** argv )
   //-- Show detected matches
   imshow( "Good Matches", img_matches );
 
-  for( int i = 0; i < good_matches.size(); i++ )
+  for( int i = 0; i < (int)good_matches.size(); i++ )
   { printf( "-- Good Match [%d] Keypoint 1: %d  -- Keypoint 2: %d  \n", i, good_matches[i].queryIdx, good_matches[i].trainIdx ); }
 
   waitKey(0);